EP3472393B1 - Manhole cover for shafts, channel access or drainage channels - Google Patents

Description

The invention relates to a manhole cover for manholes, sewer entrances or drainage channels in traffic areas.

In particular when used in street areas, it is necessary for the manhole covers to be able to bear the load of heavy vehicles, for example trucks. If use is planned, for example, on pedestrian paths or in pedestrian zones or also in driveways, lower load classes are usually sufficient, since there is usually no heavy goods traffic here.

Corresponding manhole covers are currently made of cast iron, for example, and a concrete insert can be placed in the manhole cover, which forms the surface of the manhole cover. The concrete insert can be machined to obtain a smooth surface, for example.

The disadvantage of the corresponding manhole covers, however, is their very high weight, which is particularly disadvantageous when the manhole, the access to the sewer or the drainage channel is to be opened for maintenance purposes, for example. Opening requires great physical exertion, which can lead to damage to the health of the workers employed. Therefore, it is desirable to manufacture manhole covers with a lower mass.

For manhole covers with lower load-bearing requirements, for example for use on footpaths, in private driveways or on terraces, it is already known to use plastic in order to minimize the mass of the manhole cover. However, due to their structure, these cannot be used for higher load classes, especially not for load class D4UU.

From the document KR20110127824 a chess cover according to the preamble of claim 1 is known.

The object of the present invention was therefore to provide a manhole cover for manholes, sewer accesses or drainage channels, in particular for high load classes, which has a lower weight than the previously known manhole covers.

This object is achieved by a manhole cover for manholes, sewer accesses or drainage channels according to claim 1.

Surprisingly, it has been shown that by using a reinforcing element and constructing the manhole cover with a body made of plastic, it is possible to obtain a manhole cover that also meets the requirements for high load classes, for example class D400 according to DIN EN 124-1: 2015-09 or DIN EN 1433:2005-05 or DIN 19580: 2010-07 or higher and has a significantly lower weight than the currently used manhole covers made of cast iron or a composite of cast iron and concrete. Of course, such a manhole cover is also sufficient for lower load classes, for example A15, B125, C250 according to DIN EN 124-1:2015-09 or DIN EN 1433: 2005-05 or DIN 19580: 2010-07

In the context of the present invention, shafts are both downcomers and accesses, for example to gas lines, water lines or power and telecommunications lines and to fittings that are used in such lines. Sufficient static strength and dimensional stability is achieved if the plastic body is made up of materially bonded elements with essentially the same wall thickness. Essentially the same wall thickness means that the wall thickness of the individual elements does not deviate from one another by more than 50%. The individual elements of the plastic body are ribs or ribs combined with base plates. When the manhole cover is installed, the base plate runs parallel to the surface surrounding the manhole, sewer access or drainage channel. The body can be constructed both with and without a base plate. It is possible that the plastic body is constructed only of ribs perpendicular to the surface surrounding the manhole, sewer access or drainage channel. According to the invention, the ribs are either perpendicular to the surface surrounding the manhole, sewer entrance or drainage channel or at an angle of more than 45° to the surface surrounding the manhole, sewer entrance or drainage channel. Preferably, the ribs are oriented at an angle of between 80° and 90° to the surface surrounding the manhole, sewer access or drainage channel, an angle of 90° meaning that the ribs are perpendicular to the surface.

In order to obtain an even load distribution in the plastic body, the ribs run in at least two directions, so that the ribs intersect at at least one crossing point. The ribs can form a lattice, for example, or run in a star shape towards a central point. In the case of a star-shaped arrangement of ribs, it is also possible to also provide ribs which enclose the central point in a ring-shaped manner, with a rib section of the rib enclosing the central point in a ring-shaped manner lying between two of the ribs arranged in a star-shaped manner. The rib section can be straight or curved. However, it is preferred if the ribs form a lattice, that is, are present as a cross-rib structure.

The outer circumference of the manhole cover can have any shape, the shape corresponding to the shape of the cross-section of the manhole or sewer access or drainage channel to be covered. Common shapes of the outer perimeter of the manhole cover are a circular shape, a rectangular shape, or an oval shape.

In a first embodiment of the invention, the reinforcement element is curved. In this case, the reinforcing element can be curved either downwards, ie concave, or upwards, ie convex, when viewed from above on the installed manhole cover. When the reinforcing element is curved downwards, the lowest point of the reinforcing element is in the central area of the manhole cover when the manhole cover is installed, whereas the highest point of the reinforcing element is in the central area of the manhole cover when the reinforcing element is curved upwards. The highest point with the reinforcing element curved upwards or the lowest point with the reinforcing element curved downwards is preferably located in the center of the manhole cover. The reinforcement element is preferably curved upwards. However, this is not possible in particular when the support surface on which the manhole cover rests after assembly has only a small depth. In order to enable flush installation, the manhole cover may only have a small thickness at the edge in this case. The greatest thickness of the manhole cover is in the center of the manhole cover. In order to obtain an even surface, a downward curvature that protrudes into the shaft, sewer access or drainage channel is necessary.

In contrast, a manhole cover with a reinforcing element that is curved upwards has the greatest thickness at the edge and the smallest thickness in the middle of the manhole cover. This requires a correspondingly deep support surface for mounting in order to enable flush mounting.

Irrespective of whether the reinforcement element is curved upwards or downwards, the body made of plastic lies on the reinforcement element, so that the reinforcement element lies at the bottom when the manhole cover is installed and it is therefore possible for the reinforcement element to lie on the support surface and not to rest when the manhole cover is installed plastic material. This has the advantage, in particular, that when the manhole cover is heavily loaded, there is no damage to the contact surface of the manhole cover, for example cracks or spalling on the body made of plastic material.

In one embodiment of the invention, the reinforcing element curved upwards or downwards is designed without openings or holes. In an alternative embodiment, openings or holes are formed in the arched reinforcement element, which can serve, for example, for ventilation of the shaft or sewer access or the drainage channel. Furthermore, water can also drain from the surface into the shaft, sewer access or drainage channel through corresponding holes in the reinforcement element. Both for the ventilation function and for the function as a water drain, it is necessary for the plastic body to have openings through which air and/or water can flow, particularly at the positions at which the openings or holes are formed in the reinforcing element.

In one embodiment of the invention, the upwardly or downwardly curved reinforcing element is not made in the form of a plate but is made up of curved strips which converge in the middle of the reinforcing element. The strips are curved in such a way that, depending on how the reinforcement element is installed, either the highest point of the reinforcement element or the lowest point of the reinforcement element is in the middle of the manhole cover. From the outside to the middle of the manhole cover, the strips have a parabolic, hyperbolic or elliptical course or have the shape of an arc of a circle. Irrespective of the shape of the curvature of the individual strips, however, it is preferred if the curved progression from the edge through the middle to the edge of the manhole cover is continuous.

If the reinforcement element is made up of strips, it is particularly preferred if the strips run in a star shape from the center of the reinforcement element to the edge. The ends of the strips can be connected to an outer circumferential strip. The shape of the outer peripheral strip is dependent on the shape of the manhole cover. The shape of the outer peripheral strip preferably corresponds to the shape of the manhole cover, so that in the case of a round manhole cover the peripheral strip is also round, whereas in the case of a square manhole cover the outer peripheral strip is also angular.

In another embodiment, the reinforcing member comprises an outer peripheral strip and a central plate each connected to the plastic body, wherein the central plate or an axially extending rod connected to the central plate penetrates the outer peripheral strip Spokes, rods or ropes is connected. In the manhole cover, the plastic body can enclose the spokes, rods or cables or rest on the spokes, rods or cables.

If the plastic body encloses the spokes, rods or cables, the reinforcing element is preferably overmoulded during manufacture of the manhole cover. In a design in which the body made of plastic rests on the spokes, rods or cables, it is possible to manufacture the reinforcement element and body made of plastic in two independent production steps and then to join them together, for example by screwing, clipping, welding, gluing or riveting associate.

In a further embodiment, it is also possible to design the reinforcement element in such a way that beads are formed in the reinforcement element. It is possible to use a flat plate as a reinforcement element and to form the beads in the flat plate, or alternatively to design the reinforcement element to be arched as described above and to additionally introduce beads. The beads are preferably arranged in such a way that between the beads are strips, respectively, which extend from the center of the reinforcement element towards the edge. This results in an essentially triangular shape for the beads, in which the width of the beads decreases from the outside towards the center of the reinforcement element. As a result, the strips are arranged essentially in a star shape between the beads. As an alternative to introducing beads, it is also possible, for example, to design the reinforcement element in a wavy manner, with the waves being designed in such a way that they converge centrally on a center point of the reinforcement element.

The reinforcing element designed with beads or the corrugated reinforcing element can also have additional openings or holes to allow ventilation of the manhole or sewer access or the drainage channel or to allow water to flow from the manhole cover into the manhole, sewer access or the drainage channel can drain.

If the reinforcement element is designed with a peripheral strip, it is possible to provide openings or holes in the peripheral strip, through which ventilation or aeration or water drainage is possible. Alternatively, however, it is also possible to use the open areas between the arched strips or between the spokes, rods or cables for ventilation or water drainage.

In a further embodiment, it is also possible to design the reinforcement element from crossing vertical elements. The vertical elements are preferably flat on the side running to the surface of the road when the manhole cover is in place and can be curved on the opposite side, ie pointing into the manhole, sewer access or drainage channel. In order to connect the vertical elements to one another, it is possible, for example, to make slots in them and thus to plug the individual crossing elements running vertically into one another. Alternatively, it is of course also possible to weld the individual elements together. However, it is preferred to plug the elements into one another. In such a design with vertical elements of the reinforcing element, these are enclosed with the plastic body to produce the manhole cover. For this purpose, it is particularly preferred to insert the reinforcement element into an injection molding machine and to overmold the reinforcement element to produce the body from plastic. In order to obtain a flat surface, it is also advantageous to provide a cover plate, this preferably also having vertical ribs and optionally a base plate, the cover plate resting with the ribs on the reinforcing element if no base plate is provided or with the Base plate if a base plate is provided. The distance between the ribs with which the plate rests on the reinforcement element for covering purposes is smaller than the distance between the individual elements from which the reinforcement element is made. This achieves a better distribution on the reinforcement element.

According to the invention, the material of the reinforcement element is metal. Another suitable material is ceramic or reinforced plastic, with preference being given to using a plastic reinforced with continuous fibers when using a reinforced plastic. In particular, when the reinforcement element is curved downwards, or consists of a peripheral strip and a central plate connected to rods, spokes or cables, the reinforcement element is made of a metal or a plastic reinforced with continuous fibers, in particular a metal, since the Reinforcement element is loaded in this case in particular to train and therefore a stable material for tensile loads must be used. In contrast to this, the reinforcement element is subjected to pressure in an upwardly curved embodiment, so that materials should be used here that are stable with respect to pressure loads, with metals being preferred here as the material for the reinforcement element.

Ferrous metals, for example cast iron or steel, are particularly preferred as material for the reinforcing element. The advantage of using steel is its greater plastic deformability. This has the advantage that a reinforcement element made of steel can be manufactured with a smaller thickness and thus with a lower mass than a reinforcement element made of cast iron. A further advantage of using steel for the reinforcement element is that it can be formed by conventional processing methods suitable for steel. For example, it is possible to stamp the shape of the reinforcement member from a steel plate and form it by deep drawing.

For example, a reinforcing element having a peripheral edge and a central plate, the peripheral edge and the central plate being connected by strips, can be obtained by stamping or cutting out an inner part comprising the central plate at the radially extending Strips are formed, creating from a circular plate. This results in a second part which has the outer edge with strips extending towards the center. Preferably, the strips connected to the outer edge are of the same width as the strips projecting outwards from the central panel. To form the reinforcing element, both the part with the outer edge and inwardly projecting strips and the part with the central plate and outwardly projecting strips can then be formed into the curved shape desired for the reinforcing element and then the inwardly projecting strips and the outwardly projecting strips are connected to one another, for example by welding, in order to obtain a reinforcement element. In addition to welding the inwardly and outwardly protruding strips, any other connection of metallic components, for example riveting, screwing, gluing or mutual hooking, is of course also possible. However, mutual hooking of the strips is preferred.

Any duroplastic or thermoplastic material can be used as the material for the plastic body. A thermoplastic material is preferably used, since this is easier to injection mold and to recycle. Suitable thermoplastics are, for example, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT); polyamide (PA); Polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polycarbonate (PC), styrene-acrylonitrile copolymer (SAN), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene-acrylic ester (ASA), polyoxymethylene (POM), polymethyl methacrylate (PMMA), polystyrene ( PS), syndiotactic polystyrene (SPS), polyphthalamide (PPA), polyphenylene sulfide (PPS). Of these, preference is given to polyamide (PA), polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE) and polycarbonate (PC). Polyamide 6 or polyamide 6.6 is particularly preferred as the plastic.

If a thermosetting plastic is used as the material for the plastic body, formaldehyde molding compounds, for example phenol formaldehyde resin (PF), resorcinol formaldehyde resin (RF), cresol formaldehyde resin (CF), are suitable, for example. Xylene Formaldehyde Resin (XF), Furfuryl Alcohol Formaldehyde Resin (FF), Melamine Formaldehyde Resin (MF), Urea Formaldehyde Resin (UF), Melamine Urea Formaldehyde Resin (MUF), Melamine Urea Phenol -Formaldehyde resin (MUPF), unsaturated polyester resins (UP), vinyl ester resins (VE), phenacrylate resins, vinyl ester urethanes (VU) epoxy resins (EP), diallyl phthalate resins, allyl ester (PDAP), silicone resins (SI), polyurethanes (PUR).

To modify the properties of the plastic, the plastic can contain at least one filler for reinforcement. The reinforcing filler may be in fibrous or particulate form. For example, carbon fibers, glass fibers, glass beads, amorphous silica, asbestos, calcium silicate, calcium metasilicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica, barium sulfate and feldspar can be used.

In order to achieve adequate reinforcement, in particular adequate tensile or compressive strength, it is preferred that the filler for reinforcement is in the form of fibers.

Preferred fibrous fillers are glass fibers, carbon fibers, aramid fibers and potassium titanate fibers. Glass fibers are particularly preferred here. The fibrous fillers can be used as rovings, mats or chopped glass in the commercially available forms.

The fibers are particularly preferably used as short fibers or long fibers and usually have a length in the range from 0.1 to 14 mm. The diameter of the fibers is preferably in the range from 5 to 20 μm.

The surface of the fillers can be pretreated to improve adhesion with the thermoplastic.

The proportion of fillers in the plastic is preferably in the range from 10 to 70% by weight, in particular in the range from 40 to 65% by weight, based on the total mass of the plastic including all additives.

The plastic can also contain customary additives. Customary additives are, for example, impact modifiers, plasticizers, UV stabilizers, dyes, stabilizers and mold release agents. Any additives known to those skilled in the art can be used here. The additives are added in amounts customary in the art.

Irrespective of whether the plastic body has a base plate in addition to the ribs, in one embodiment of the invention the plastic body is designed to have a flat plate which rests on the ribs and is connected to the ribs. The plate resting on the ribs makes it possible to obtain a surface of the manhole cover that is preferably structured in order to avoid accidents due to a surface that is too smooth. Such accidents can occur particularly when the surface is damp or wet and a pedestrian or vehicle slides on it. Alternatively, it is also possible to introduce a pattern or a pictorial representation into the plate. Corresponding pictorial representations can be of a purely artistic nature in order to obtain a visual enhancement of the manhole cover. Alternatively, however, it is also possible to incorporate, for example, company logos or advertising in the form of a relief into the surface of the panel. However, a smooth surface is preferred.

As an alternative to forming the plate from plastic, it is also possible to provide an upper plate made from the same material as the reinforcement element. In this case, the material of the reinforcement element encloses the plastic body. Also, the top plate acts as an additional reinforcement. The reinforcing element and the upper plate are then connected to one another after the body made of plastic has been introduced, with a material connection, a form-fitting connection or a force-fitting connection being possible here. Welding or screwing are particularly suitable for the connection of the reinforcement element and the upper plate. A detachable connection is preferred in order to be able to replace individual components of the manhole cover if necessary. If the reinforcement element and the top plate are screwed together, it is also possible to use a screw connection with which the manhole cover is screwed to the bearing surface of the manhole or sewer access or drainage channel.

Irrespective of the shape of the reinforcement element, the plastic body can be connected to the reinforcement element in a positive or non-positive manner. A form-fitting connection is obtained, for example, if the body is made of plastic using an injection molding process and the reinforcing element is placed in the mold before the plastic is injected, so that the plastic can be overmolded.

Due to the different thermal expansion of the reinforcement element and plastic material, however, it is preferred to connect the plastic body to the reinforcement element in a non-positive or positive manner at selected positions and thus allow relative movement between the plastic body and reinforcement element between the fastening positions. Here, however, it is important to ensure that the body is made of plastic slidably rests on the reinforcing element. The fact that the body made of plastic rests on it ensures that loads acting on the body made of plastic, for example when a vehicle drives over the manhole cover, are evenly transmitted to the reinforcing element.

In order to connect the plastic body to the reinforcement element, it is possible, for example, to form holes in the reinforcement element, through which the plastic of the plastic body is pressed for connection to the reinforcement element, or to clip or screw the plastic body to the reinforcement element . When the plastic material is pressed through holes in the reinforcing element, the plastic is pressed through the holes in the molten state when the body is made of plastic. In order to obtain a stable connection, the amount of plastic that is forced through the holes is so great that a head is formed underneath the reinforcement member at each hole, which abuts the underside of the metal reinforcement member and has a larger diameter than that hole. As an alternative to the connection by injecting the plastic through holes in the reinforcement element, it is also possible, as already described above, to encapsulate the reinforcement element with the plastic.

A further possibility for connecting the body made of plastic to the reinforcing element is screwing or clipping. If the body made of plastic is to be screwed to the reinforcing element, it is possible, for example, to provide through-holes both in the reinforcing element and in the body made of plastic, through which screws are passed, which are fastened with nuts. Alternatively, threads can be formed in the reinforcement element and through-holes in the plastic body or threads can be formed in the plastic body and through-holes in the reinforcement element and screws can be guided through the through-holes and screwed into the thread in the reinforcement element or in the plastic body. Another possibility for screwing is to form short threaded rods on the reinforcing element or on the plastic body, which are guided through through-holes in the other part and fixed with nuts. If the plastic body and the reinforcement element are to be clipped together, the clips can either be attached to the components or separate clips can be used.

In addition to injection molding, overmoulding, screwing or clipping, any other possibility for connecting the body made of plastic and the reinforcing element is also possible, for example riveting or gluing.

Furthermore, it is also possible to implement overmolding, in which the body made of plastic encloses the reinforcing element on the outer circumference.

However, preference is given to connections that allow displacement relative to one another in order to be able to compensate for thermal stresses in the event of different thermal expansions.

In order to prevent the manhole cover from being easily removed from the manhole, sewer access or drainage channel due to its low weight, it is also preferred if countersunk holes are formed in the manhole cover, through which the manhole cover with the bearing surface on the manhole, sewer access or the drainage channel can be screwed. In order to remove the manhole cover, it is necessary to first loosen the screws that fasten the manhole cover.

Exemplary embodiments of the invention are shown in the figures and are explained in more detail in the following description.

• Figur 1 eine Schachtabdeckung mit nach oben gewölbtem Verstärkungselement,
• Figur 2 eine Schachtabdeckung mit nach unten gewölbtem Verstärkungselement,
• Figur 3 ein Verstärkungselement mit mehreren gewölbten Streifen,
• Figur 4 zwei Einzelteile, die zusammengefügt das in Figur 3 dargestellten Verstärkungselement ergeben,
• Figur 5 ein Verstärkungselement mit einem umlaufenden äußeren Streifen und einen zentralen Stapel, der mit Speichen am äußeren umlaufenden Streifen befestigt ist,
• Figur 6 ein Verstärkungselement mit einem umlaufenden äußeren Streifen und einer zentralen Platte, die mit Speichen am äußeren umlaufenden Streifen befestigt ist,
• Figur 7 ein Verstärkungselement mit wellenförmig ausgebildeten Sicken,
• Figur 8 einen Ausschnitt aus einer Schachtabdeckung mit einem unteren Verstärkungselement, einer oberen Platte aus dem gleichen Material wie das Verstärkungselement, einen Körper aus Kunststoff zwischen den metallischen Teilen und äußeren Ummantelung aus Kunststoff,
• Figur 9 einen Ausschnitt einer Schachtabdeckung mit einem Verstärkungselement, einer oberen Platte und einem dazwischen liegenden Körper aus Kunststoff in einer ersten Ausführungsform,
• Figur 10 einen Ausschnitt einer Schachtabdeckung mit einem Verstärkungselement, einer oberen Platte und einem Körper aus Kunststoff in einer zweiten Ausführungsform,
• Figuren 11.1 bis 11.4 verschiedene Rippengeometrien für den Körper aus Kunststoff,
• Figur 12 einen Schnitt durch eine Schachtabdeckung mit vertikal ausgerichteten Elementen zur Bildung des Verstärkungselements.

Show it:

• figure 1 a manhole cover with a reinforcing element curved upwards,
• figure 2 a manhole cover with a downwardly curved reinforcement element,
• figure 3 a reinforcement element with several arched strips,
• figure 4 two pieces that put together the in figure 3 shown reinforcing element result,
• figure 5 a reinforcement member having a peripheral outer strip and a central stack attached to the outer peripheral strip with spokes,
• figure 6 a reinforcement member having a peripheral outer strip and a central plate attached to the outer peripheral strip with spokes,
• figure 7 a reinforcement element with wavy beads,
• figure 8 a section of a manhole cover with a lower reinforcement member, a top plate of the same material as the reinforcement member, a body of plastic between the metal parts and outer casing of plastic,
• figure 9 a detail of a manhole cover with a reinforcement element, a top plate and an intermediate body made of plastic in a first embodiment,
• figure 10 a section of a manhole cover with a reinforcement element, a top plate and a body made of plastic in a second embodiment,
• Figures 11.1 to 11.4 different rib geometries for the plastic body,
• figure 12 a section through a manhole cover with vertically aligned elements to form the reinforcement element.

figure 1 shows a section through a manhole cover with an upwardly curved reinforcing element.

A manhole, a sewer access or a drainage channel is covered with a manhole cover 1. For this purpose, the shaft, sewer access or drainage channel has a bearing surface 3 . The bearing surface 3 runs around the shaft, sewer access or drainage channel along the perimeter.

According to the invention, the manhole cover has a reinforcing element 5 and a body 7 made of plastic. In the embodiment shown here, the plastic body comprises ribs 9 and a plate 11 resting on the ribs 9. The plate 11 resting on the ribs 9 is usually cohesively connected to the ribs. A smooth surface of the manhole cover 1 can be achieved by the plate 11 lying on it.

In order to connect the body made of plastic 7 to the reinforcing element 5, it is preferred if holes are formed in the reinforcing element 5 through which the plastic compound can flow. Extensions 13 form below the holes in the reinforcement element 5, so that a stable connection of the reinforcement element 5 and the body 7 made of plastic is obtained. A corresponding attachment can be achieved, for example, by the body 7 being injection molded from plastic and the reinforcing element 5 being inserted into the mold during the injection molding. Alternatively, it is also possible to manufacture the body 7 from plastic and the reinforcement element 5 separately and then to attach them to the reinforcement element 5 by clipping, stapling, gluing or screwing, for example. However, it is preferred to connect the reinforcing element 5 and the body 7 made of plastic by means of injection molding during the manufacturing process of the body 7 made of plastic.

figure 2 shows a manhole cover with a downwardly curved reinforcing element. In the figure 2 manhole cover 1 shown differs from that in figure 1 illustrated by the direction in which the reinforcing member 5 is curved. In contrast to the in figure 1 illustrated embodiment is in the in figure 2 illustrated embodiment, the reinforcing element 5 is curved downwards. This allows the manhole cover 1 to be used, for example, in manholes, sewer accesses or drainage channels where the distance between the bearing surface 3 and the surface 15, for example a road surface, is less than that in figure 1 illustrated embodiment. Apart from the direction of curvature of the reinforcing member 5, the structure is as shown in FIGS Figures 1 and 2 illustrated embodiments accordingly.

Both at the in figure 1 illustrated embodiment as well as in the in figure 2 illustrated embodiment, it is possible to provide the overlying plate 11 shown here to to get a smooth surface. Alternatively, however, it is also possible to dispense with the overlying plate 11, so that the plastic body 7 is constructed solely from ribs 9. Furthermore, it is also possible to provide a base plate, this being shaped for example so that it rests on the reinforcement element 5 or runs centrally in the plastic body 7, so that the ribs 9 extend upwards and downwards from the base plate. The base plate can be provided both in an embodiment with a plate 11 lying on it and without a plate 11 lying on it.

The reinforcement element 5 can be a full-surface plate, for example.

An alternative embodiment for a reinforcement element is in figure 3 shown.

At the in figure 3 In the embodiment shown, the reinforcement element 5 comprises a peripheral strip 17 and a central plate 19. The peripheral strip 17 and the central plate 19 are connected to one another with curved strips 21. The curved strips 21 result in an arching of the reinforcing element 5. The orientation for producing the manhole cover is as in FIGS Figures 1 and 2 possible, i.e. curved upwards or curved downwards.

figure 4 shows two individual parts that make up the in figure 3 reinforcement element shown can be constructed.

In this case, the reinforcing element 5 is constructed from two individual parts, in which the first part 23 has the circumferential strip 17 and strips 25 extending towards the center of the reinforcing element 5. The second part 27 has the central plate 19 and outwardly extending strips 29 on. In order to manufacture the first part 23 and the second part 27, it is possible, for example, to punch the second part 27 out of a round plate. With a corresponding design of the outwardly extending strips 29, the remainder after punching is the first part 23 with the circumferential strip 17 and the strip 25 extending towards the center. For this purpose, the strips 25, 29 are preferably designed so that the width of center extending strip 25 on the first part 23 on the inner circumference of the circumferential strip 17 corresponds to the outer width of the outwardly extending strips 29 of the second part 27. Correspondingly, the width of the centrally extending strips 25 of the first part 27 at the end thereof corresponds to the width of the outwardly extending strips 29 of the second part 27 at the periphery of the central plate 19. After the first part 23 and the second part 27 have been manufactured these are reshaped to form the bulge. A pressing process, for example a deep-drawing process, can be used for this purpose. After forming, the strips 29 of the second part and the strips 25 of the first part are connected to one another. In order to obtain a stable connection, the strips 25, 29 are welded to one another, for example. For a stable connection, it is particularly preferred if the second part 27 for connecting the strips 25, 29 is inserted into the first part 23. In addition to welding, however, any other method for connecting the two parts 23, 27 is also possible, for example screwing, riveting or gluing. It is also possible to connect the two parts 23, 27 by overmolding with the plastic mass for the body 7 made of plastic.

An embodiment of a reinforcement element with an outer circumferential strip and a bar, the bar and the circumferential stiffener being connected to one another with spokes, is disclosed in US Pat figure 5 shown.

This in figure 5 The reinforcing element shown comprises a peripheral strip 17 and a bar 31. A plate 33 can also be attached to the bar 31, with a force acting on the plate 33 when a load is applied. In order to transmit the force acting on the plate 33 to the peripheral strip 17 as well, the rod 31 on which the plate 33 rests is fastened to the peripheral strip 17 with spokes 35 . As an alternative to the spokes 35, it is also possible to use ropes or strips made of the same material as the circumferential strip 17 and the rod 31 with which the rod 31 is attached to the circumferential strip 17. Steel or any material that can withstand tensile loads is particularly suitable as a material for ropes.

As an alternative to the design with a bar and a top plate, it is also possible to use the reinforcement element as in figure 6 shown with a peripheral strip 17 and a central panel 19, the central panel 19 being different from that shown in Fig Figure 3 and 4 illustrated embodiment is not fastened to the peripheral strip 17 with wide strips, but with spokes 35. Here, too, it is possible as an alternative to the spokes 35 to fasten the central plate 17 to the peripheral strip 17 by means of ropes.

Another possible design for a reinforcement element 5 is in figure 7 shown. At the in figure 7 illustrated embodiment, the reinforcement element 5 has a wave-shaped outer circumference 37 . The waves extend to the center 39 of the reinforcement element 5, so that the waves become smaller toward the center.

Instead of the in figure 7 illustrated wavy design, it is also possible to bring 5 any beads in the reinforcing element. A bead shape that essentially corresponds to that in figure 7 corresponds to the waveform shown, namely beads that are wider at the outer periphery and whose width decreases towards the center. In this case, the beads do not necessarily have to extend as far as the center point 39 , but can end at a distance from the center point 39 .

figure 8 shows a section of a manhole cover with a curved reinforcement element and additionally a second plate made of the same material as the reinforcement element, the body being made of plastic between the reinforcement element and the further plate.

At the in figure 8 illustrated embodiment, the manhole cover 1 has a reinforcing element 5, which is curved downwards. The reinforcing element can Example like the one in figure 2 be executed shown. In addition to the reinforcement element 5, the manhole cover 1 of FIG figure 8 embodiment shown has a top plate 41. The body 7 made of plastic is positioned between the reinforcing element 5 and the top plate 41. In the embodiment shown here, the plastic body has vertically running ribs 9 and a base plate 43. The ribs 9 extend from the base plate 43 upwards and downwards. The body 7 made of plastic rests with the ribs 9 on the reinforcement element 5 and the upper plate 41 on the ribs 9 extending upwards from the base plate 43.

In order to obtain a smooth surface, the in figure 8 illustrated embodiment, an outer casing 45 made of plastic is provided. The outer casing 45 made of plastic encloses the reinforcing element 5, the top plate 41 and the body 7 made of plastic. The same plastic can be used as the material for the plastic body 7 and the outer casing 45 . However, it is also possible to use different polymers.

Two further alternative embodiments for a manhole cover with a reinforcement element 5, a top plate 41 and a plastic body 7 positioned between the reinforcement element 5 and the top plate 41 are shown in FIGS Figures 9 and 10 shown.

In contrast to the in figure 8 embodiment shown have in the Figures 9 and 10 illustrated embodiments no outer casing 45 made of plastic. However, it is also possible also in the Figures 9 and 10 illustrated embodiments with an outer casing 45 to carry out. It is also possible to refer to the outer casing 45 in the in figure 8 to waive illustrated embodiment.

At the in figure 8 illustrated embodiment, the reinforcing member 5 and the top plate 41 are connected to each other at the edge via a flange connection. The connection can take place in a form-fitting, material-fitting or force-fitting manner, with a force-fitting connection, for example by screwing or riveting, being preferred. If an outer casing 45 made of plastic is provided, the additional connection of the reinforcement element 5 and the upper plate 41 can also be dispensed with, since these are positioned and held in relation to one another by the outer casing 45 .

At the in Figures 9 and 10 In the illustrated embodiments, an elastomeric connection 47 is provided for connecting the reinforcement element 5 and the upper plate 41 . At the in figure 9 In the illustrated embodiment, the elastomeric compound 47 encloses the top plate 41 along its outer perimeter and is positioned in the horizontal plane between an upwardly extending edge 49 of the reinforcement member 5 and the top plate 41 . In contrast to this, the elastomer connection 47 in the in figure 10 the embodiment shown is positioned on the outer edge of the reinforcement element 5 and the top plate 41 rests on the elastomeric connection 47 .

The use of an elastomeric connection 47 has the advantage that different thermal expansions of the individual components can thereby be compensated.

As an alternative to the in figure 10 illustrated embodiment with an elastomeric connection 47, it is also possible to provide a positive connection or a non-positive connection.

In the Figures 11.1 to 11.4 different variants for the arrangement of ribs in the body 7 made of plastic are shown. Here, the body 7 made of plastic at the in Figures 11.1 to 11.3 illustrated embodiments a circular cross-section on and at the in Figure 11.4 illustrated embodiment has a square cross section. The shape of the plastic body 7 usually corresponds to the shape of the manhole cover 1. In the case of a round manhole cover 1, the plastic body 7 is also round, and in the case of a square manhole cover 1, the plastic body 7 is also square.

At the in Figures 11.1 to 11.4 In the illustrated embodiments, the ribs form a rectangular division, with a square division, as illustrated, being preferred here. Here, the individual ribs 9 of the body 7 made of plastic intersect at an angle of 90°. However, as an alternative to the square division shown here, it is also possible to provide, for example, a triangular division or any other division, in which case the ribs 9 intersect at an angle other than 90°.

At the in Figure 11.2 illustrated embodiment, the ribs 9 extend radially from the center of the plastic body 7 to the outer edge. It would also be possible to have the ribs extend outwards from an off-centre point, but it is preferred if the ribs extend radially from the center point 39 of the plastic body 7 to the outer edge.

In addition, ribs 9 can be provided which annularly enclose the center point 39 of the body 7 made of plastic. This is an example in Figure 11.3 shown. The ribs annularly enclosing the center 39 intersect the ribs 9 running radially outwards from the center 39.

Of course it is also possible in the Figures 11.2 and 11.3 variants shown for a body 7 made of plastic with any other cross-sectional area, such as a rectangular or square cross-sectional area.

In addition to the courses of the ribs 9 shown here, any other desired orientation of the ribs 9 known to those skilled in the art is also possible.

An alternative embodiment for a manhole cover 1 is in figure 12 shown.

In contrast to the reinforcement elements 5 described above, in figure 12 illustrated embodiment, the reinforcing element 5 is constructed from vertically extending elements. Here, the reinforcement element 5 in the in figure 12 illustrated embodiment two intersecting elements 51. The elements 51 have an angle of 90° to one another. The body 7 made of plastic rests on the reinforcing element 5 formed from the elements 51 . This has ribs 9 and a plate 11 lying on it. With the ribs 9 the body 7 made of plastic rests on the vertical elements 51 of the reinforcement element 5 .

In addition to the figure 12 illustrated embodiment with two intersecting elements 51, it is also possible to provide several elements 51. These can extend radially outwards from the center or, for example, also run parallel to one another. It is preferred here if at least one element 51 is aligned transversely to the elements 51 running parallel, so that the elements 51 aligned parallel intersect the element 51 running transversely thereto. In addition to only one element 51 running transversely to the elements 51 aligned in parallel, it is of course also possible to provide a plurality of elements 51 running parallel in both directions, so that a rectangular division results, for example. Alternatively, however, any further alignment of the vertically running elements 51 to form the reinforcing element 5 is also conceivable. So they can, for example, as in the Figures 11.2 and 11.3 variants shown for the ribs 9 of the body 7 made of plastic.

Reference List

1

manhole cover

3

bearing surface

5

reinforcement element

7

Plastic body

9

rib

11

overlying plate

13

extension

15

surface

17

circumferential stripe

19

central plate

21

stripes

23

first part

25

stripe extending towards the middle

27

second part

29

outwardly extending stripe

31

Rod

33

plate

35

spoke

37

outer perimeter

39

Focus

41

top plate

43

base plate

45

outer wrap

47

elastomer compound

49

rim extending upwards

51

element

Claims (9)

1. A manhole cover for manholes, sewer accesses or drainage channels, comprising a reinforcing element (5) and a body (7) made of plastic, which is connected to the reinforcing element (5), the manhole cover being designed to close a manhole, sewer access or drainage channel and the reinforcing element (5) being formed in such a way that it can rest on a bearing surface (3) on the manhole, sewer access or drainage channel when the manhole, sewer access or drainage channel is closed by means of the manhole cover (1), and the body (7) made of plastic comprising ribs (9), which can extend perpendicularly or at an angle of more than 45° to the surface (15) surrounding the manhole, sewer access or drainage channel when the manhole, sewer access or drainage channel is closed, the reinforcing element being manufactured from a metal, wherein the ribs (9) rest on the upper side of the reinforcing element (5), and the reinforcing element (5) also comprises one of the following features:

   - the reinforcing element (5) is arched,

   - the reinforcing element (5) comprises an outer encircling strip (17) and a central plate (19), which are each connected to the body (7) made of plastic, and the central plate (19) or a rod (31) connected to a plate (33) and extending in an axial direction is connected to the outer encircling strip (17) by spokes (35), rods or cables,

   - the reinforcing element (5) is constructed from intersecting, vertically aligned elements (51),

   - beads are formed in the reinforcing element (5).
2. The manhole cover according to claim 1, wherein the reinforcing element (5) is constructed from arched strips (21) which converge in the center of the reinforcing element (5).
3. The manhole cover according to claim 1 or 2, wherein openings are formed in the reinforcing element (5).
4. The manhole cover according to one of claims 1 to 3, wherein the plastic of the body (7) which is connected to the reinforcing element (5) is selected from thermoplastic or thermosetting polyesters, polyamide, polyvinylchloride, polypropylene, polyethylene, polystyrene, polycarbonate, styreneacrylonitrile copolymer, acrylonitrile-butadienestyrene copolymer, acrylonitrile-styrene-acrylic ester, polyoxymethylene, polymethylmethacrylate, syndiotactic polystyrene, polyphthalimide, polyphenylene sulfide, formaldehyde resins, unsaturated polyester resins, vinyl ester resins, phenacrylate resins, vinyl ester urethanes, epoxy resins, diallyl phthalate resins, allyl esters, silicone resins and polyurethanes.
5. The manhole cover according to one of claims 1 to 4, wherein the body (7) made of plastic has a flat plate (11), which rests on the ribs (9) and is connected materially to the ribs (9).
6. The manhole cover according to one of claims 1 to 5, wherein holes are formed in the reinforcing element (5), through which holes the plastic of the body (7) made of plastic is forced for connection to the reinforcing element (5), or wherein the body (7) made of plastic is clipped or screwed to the reinforcing element (5).
7. The manhole cover according to one of claims 1 to 5, wherein the body (7) made of plastic rests slidably on the reinforcing element (5).
8. The manhole cover according to one of claims 1 to 7, wherein the body (7) made of plastic surrounds the reinforcing element (5) at the outer circumference.
9. The manhole cover according to one of claims 1 to 8, wherein countersunk holes are formed in the manhole cover (1), through which holes the manhole cover (1) can be screwed to the bearing surface (3) on the manhole, sewer access or drainage channel.

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